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LITERARY AND SCIENTIFIC. 

 WORCESTERSHIRE NATURAL HISTORY SOCIETY. 



LECTURE " ON THE GRADUAL DEVELOPMENT OF ORGANIC LIFE.'* 



At the Guildhall, on Tuesday, December 2nd, Mr. Walsh continued the subject 

 of his former lecture, which, it will be in the recollection of our readers, was " On 

 the Gradual Development of Organic Life;" he now confined his attentien to the 

 development of one set of organs, viz. — those of circulation and respiration. 

 With the aid of several very beautiful diagrams, he explained the form of the 

 heart as it is found in the different series of animals, having previously alluded to 

 the sanguineous system of the higher zoophytes and the insects in which there is no 

 true circulation, the blood simply oscillating from one extremity of the vessel to 

 the other ; but these, he observed, have a circulation, though not of blood, in them. 

 The air pervades the whole body, while the blood is confined to a simple reservoir, 

 exactly the reverse of what takes place in the higher animals. 



The first beings in which we find a true heart belong to the department 

 MoUusca; here, as in fishes, it consists of a single auricle and ventricle, one for 

 the reception of the returned blood, the other for its transmission thiough the gills to 

 all parts of the body. In the reptiles we notice several gradations — first, in the 

 turtle we have two auricles and one ventricle, both of the auricles empty their 

 blood into the ventricle, one, however, contains black blood, which is unfit for 

 nutrition and secretion, the other filled by blood which, having passed through the 

 lungs, has become altered in its character, in fact arterialized, as it is termed, by 

 physiology ; in this way the whole system is supplied with imperfectly changed 

 blood. In serpents, we find two auricles and two ventricles, but as if to complete 

 the chain, the two ventricles communicate with one another, and are, consequently, 

 but one cavity. The crocodile was next especially alluded to, as having a perfect 

 heart, but with a peculiar system of circulation, by which, while the head and 

 anterior part of the body is supplied with blood completely purified, the blood which 

 passes to the posterior position is only partially so — this peculiar arrangement 

 being adopted apparently because the brain in this animal is more perfectly de- 

 veloped than in others of the same class. 



Finally he proceeded to show the circulating and respirating system of birds and 

 mammalia, which differ chiefly in the structure of their lungs. In birds these 

 organs are solid fleshy masses, and permit the air to pass through them into the 

 large air cell beyond — whilst in the mammalia the lungs themselves are cellular 

 and admit the air into them. To shew more distinctly the structure of the hearts 

 of higher animals, Mr. Walsh exhibited a cow's heart, and explained how admirably 

 it was contrived to fulfil its office ; the curious construction of the cup-like valves 

 by which the reflux of the blood was prevented — the superior muscular strength of 

 the left ventricle (compared with the right), to enable it to propel the blood to 

 different parts of the body — and many other interesting circumstances, were 

 pointed out, all tending to shew design and contrivance. The lecture was indeed a 

 most instructive one in this point of view, and the acclamation of the company at 

 the conclusion testified the pleasure they had received. Mr. Walsh intimated that 

 he should at some future time continue the subject. Thanks to the lecturer were 

 moved by Sir Charles Throckmorton, Bart, and seconded by Mr. O. Lloyd. 



LECTURE "on THE MAD CHARACTERS OF SHAKSPEARE, AND 

 PARTICULARLY ON THAT OF HAMLET." 



Mr. Walter's lecture on the madness of some of the characters in Shakspeare's 

 Plays, and in particular on that of Hamlet, was delivered at Mr. Deighton's 

 News-room, on Tuesday evening, the 23rd of December. 



